There is sufficient evidence to demonstrate the capacity for reorganization of the mature mammalian cerebral cortex as a function of experience following brain injury. The use of physical and pharmacological interventions has been used to alter the post-infarct behavioral experience of animals following cortical lesions, and anatomical and functional recovery has been analyzed primarily within motor systems. The mystacial vibrissae of the rat, with their corresponding representation in the somatosensory cortex, provides an ideal vehicle for studies dealing with damage and subsequent recovery in the central nervous system. We have developed a surgical model that results in ischemic damage confined to the posteriomedial barrel subfield (PBMSF) of the first somatosensory cortex of the rat. Damage to the PBMSF results in a loss of tactile discrimination using the mystacial vibrissae. The recovery of sensory function can be examined using a gap crossing test in which animals discriminate between two textures. Preliminary data obtained using this model indicates that early physical intervention in the form of short bouts of whisker stimulation results in a dramatic acceleration in the rate of functional recovery in this sensory system. This project is designed to determine an optimal rehabilitation paradigm for the recovery of sensory function following ischemic injury to the cerebral cortex of the rat. The focus of this research will be to examine factors that optimize functional recovery and maximize the anatomical and physiological reorganization of the central nervous system (CNS) following central lesions. By examining the effect of types, duration and intensity of intervention on the behavioral and anatomical data from the same animal, we will provide important information regarding 1) an optimal mode of intervention; 2) how different modes of training maximize or limit CNS plasticity; and 3) the global functional activity pattern throughout the central neuraxis and the "path" of effective connectivity along that neuraxis.